Medical history is replete with attempts to manipulate the immune system with chemical, biochemical and cellular means. Many experimental protocols have been tried in which agents thought to enhance and/or increase the body's immune response to disease, including cancer, have been given to patients. Most of these trials have not been successful and in the few cases in which success has been reported it has been difficult to reproduce the successful aspects of the trial.
One of these experimental treatment protocols, known as "adoptive immunotherapy" or "cellular adoptive immunotherapy", involves the administration of immunologically active (immunocompetent) cells to an individual for the purpose of providing a beneficial immunological effect to the individual (e.g., reduction or control of cancerous or diseased tissue). These immunocompetent cells can be taken by venipuncture or leukopheresis either from the individual to be treated (autologous treatment) or from another individual (allogeneic treatment). The lymphocytes are cultured to increase their number and activate their antitumor activity and are then infused back into the patient. Animal experiments transferring immunocompetent cells from healthy animals to animals with cancerous tumors have suggested that adoptive immunotherapy can illicit an anti-tumor effect in certain tumor models with a high degree of effectiveness.
Samples of fresh (i.e., untreated) peripheral blood lymphocytes ("PBL"), a subclass of lymphocytes, are capable of lysing certain established tumor lines (e.g., K562) without any activation or treatment in the laboratory. West et al., J. Immunol. 118:355 (1977). Cells that can lyse these established tumor lines, including K562, have been designated natural killer ("NK") cells.
Populations of fresh PBL that have NK activity are, however, unable to lyse tumor lines such as Daudi, HL60 or fresh tumor targets (each being referred to herein as "NK resistant" targets). Human PBL cultured with interleukin-2 (IL-2) for as little as 3-5 days will develop the ability to lyse NK-resistant targets. Grimm et al., J. Exp. Med. 155:1823 (1982); Sondel et al., J. Immunol 137:502 (1986); Zarling et al., Cancer Immunol. Immunother. 15:237 (1983); Lotze et al., Cancer Res. 41:4420 (1981). As used throughout this specification and the appended claims "IL-2" shall include (1) naturally-derived interleukin-2, (2) recombinant interleukin-2, (3) interleukin-2 from any other source, and (4) peptides [e.g., fragments, homologs and analogs] which have the same biological activity as interleukin-2 for stimulating LAK activity regardless of the source of such peptides. Cells that have acquired the ability to lyse NK resistant targets after culturing with IL-2 have been designated lymphokine-activated killer ("LAK") cells. LAK activity and NK activity are currently distinguished by the ability of LAK cells to destroy NK-resistant targets.
Rosenberg et al. have obtained encouraging results in a significant number of patients, especially those with renal cell carcinoma, melanoma, tumors of the colon and non-Hodgkin lymphoma, using a treatment protocol combining the administration of LAK cells with the systemic administration of IL-2. Rosenberg, JNCI 75:595 (1985); Shu and Nisenkig, J. Immunol 135:2895 (1985); Rosenberg et al., N. Engl. J. Med. 313:1485 (1985). The IL-2 is administered systemically in an attempt to maintain LAK activity and to activate LAK activity in uncultured cells in the bloodstream. The effectiveness of the Rosenberg treatment protocol has been severely crippled, however, by the inability of the culturing methods of Rosenberg et al. to sufficiently increase LAK cell numbers in culture and to maintain LAK activity in cultured cells for more than five days. Rosenberg, supra; Shu and Nisenkig, supra; Rosenberg et al., supra; Muul et al., J. Immunol. Metth 88:265 (1986). LAK activity in cells cultured according to the Rosenberg method is short-lived and declines rapidly after day 5 of culture.
Rosenberg has suggested that approximately 2.times.10.sup.10 to 2.times.10.sup.11 cells with adequate LAK activity are required to achieve a therapeutic response. Since a typical sample of PBLs contains only 1-4.times.10.sup.9 cells which can be activated to become LAK cells and the percentage of the cells originally taken from the lymphocyte source which, after activation and culturing by the Rosenberg method, are available for therapy has frequently been less than 100% (i.e., the number of activated cells available for infusion is less than the number of cells with which the activating culture was started), such high cell numbers can only be achieved through multiple leukopheresis and multiple LAK cell infusions which can be very hard on the health of a patient who is already severely compromised. This has made LAK cell adoptive immunotherapy a difficult, costly and medically troublesome task.
The Rosenberg treatment protocol has also been questioned due to the toxicity of systemically-administered IL-2. Some critics have proposed that many undesirable side effects, including accumulation of fluids in the lungs, fever, chills, decrease in urinary output, increase in creative and BUN levels, hyponatermia and death (in two reported cases), are the result of IL-2 administered in connection with LAK cell therapy. Rosenberg et al., N. Engl J. Med. 313(23):1485; Rosenberg et al., N, Engl. J. Med. 316(15):889. Elimination of these side effects by eliminating the need to administer IL-2 with the LAK cells would make LAK cell therapy a more tolerable and efficacious treatment.
It would therefore be desirable to provide a method for culturing lymphocytes that can produce the large number of activated cells necessary for practical and successful adoptive immunotherapy without the need to extract multiple samples of cells from a patient. It would also be desirable to provide a method for adoptive immunotherapy that does not require multiple leukopheresis or venipunctures or where the systemic administration of high doses of IL-2 can be attenuated or eliminated while still achieving anti-tumor effects.